The Constitution - The commander in chief clause

While the Framers granted Congress the authority to decide for war, they
provided in Article 2, Section 2, that: "The President shall be
Commander in Chief of the Army and Navy of the United States, and of the
Militia of the several states, when called into the actual Service of the
United States." The Framers thus vested command of the military
forces in the president, which meant that once Congress authorized
military hostilities, the president as commander in chief would exercise
authority to conduct and prosecute the war effort. As Hamilton explained
in
Federalist
No. 74: "Of all the cares or concerns of government, the direction
of war most peculiarly demands those qualities which distinguish the
exercise of power by a single hand." But the designation of the
president as commander in chief conferred no warmaking power whatever; it
vested in the president, as Hamilton proposed to the convention, only the
authority to repel sudden attacks on the United States and to direct war,
"when authorized or begun." In this capacity, he would
direct those forces placed at his command by an act of Congress.

The Framers adopted the title of commander in chief and its historical
usage from England, where it was introduced in 1639 by King Charles I. The
title was used as a generic term referring to the highest-ranking officer
in a particular chain of command or theater of action. But the ranking
commander in chief was always sub-ordinate to a political superior,
whether a king, Parliament, or, with the development of the cabinet system
in England, a secretary of war. The practice of giving the officer at the
apex of the military the title of commander in chief and of making him
subject to instructions from a political superior was embraced by the
Continental Congress and by most of the states in their early
constitutions. When, on 15 June 1775, the Continental Congress unanimously
decided to appoint George Washington as "General and Commander in
Chief, of the Army of the United Colonies," it issued instructions
that kept Washington on a short leash. He was ordered "punctually
to observe and follow such orders and directions, from time to time, as
you shall receive from this, or future Congress of these United Colonies,
or Committee of Congress." Congress did not hesitate to instruct
the commander in chief on military and policy matters. This usage had been
established for a century and a half and was thoroughly familiar to the
Framers when they met in Philadelphia. It is probable that this settled
understanding and the consequent absence of concerns about the nature of
the post accounts for the fact that there was no debate on the commander
in chief clause at the convention. It is telling, moreover, that there was
no effort at the convention or at any state ratifying convention to
redefine the office of commander in chief.

Hamilton's speech on 18 June captured the essence of the
president's power as commander in chief when he stated that the
executive was "to have the direction of War when authorized or
begun." There was no fear of the legal authority granted by the
commander in chief clause, and there is no evidence that anyone believed
that his office as commander in chief endowed the president with an
independent source of warmaking authority. The narrow, military role of
the executive was explained by Hamilton in
Federalist
No. 69, in which he said the president's power as commander in
chief "would be nominally the same with that of the King of Great
Britain, but in substance much inferior to it. It would amount to nothing
more than the supreme command and direction of the military and naval
forces … while that of the British king extends to the
declaring
of war and to the
raising
and
regulating
of fleets and armies,—all which, by the Constitution under
consideration, would appertain to the legislature." The president
as commander in chief was to be "first General and Admiral"
in "the direction of war when authorized or begun." But all
political authority remained in Congress, as it had under the Articles of
Confederation. As Madison explained it in a letter to Thomas Jefferson in
1798: "The Constitution supposes, what the History of all
Governments demonstrates, that the Executive is the branch of power most
interested in war, and most prone to it. It has accordingly with studied
care vested the question of war in the Legislature."